1. Field of the Invention
The present invention relates to a catheter and particularly to a novel structure of a catheter constructed such that two guide wires can be inserted therein or extended therethrough.
2. Discussion of Related Art
Conventionally, a catheter has been used as a sort of medical instrument that is inserted in a tubular organ of a human body, such as a blood vessel, a digestive tract, or a ureter, so as to carry out various treatments, examinations, or procedures. Generally, a catheter includes a main body that has a flexibility and is inserted in a human body. The main body of the catheter has a lumen that is formed therein and extends in an axial direction thereof. Since a guide wire that is inserted in a tubular organ of the human body is extended through the lumen of the main body, the main body can be inserted in the human body while being guided by the guide wire.
Each of Patent Document 1 (Japanese Patent Application Publication No. 2004-267333) and Patent Document 2 (Japanese Patent Application Publication No. 2002-505148) discloses a catheter that has the above-described structure and includes a main body in which two guide wires can be inserted. The main body of the catheter has two lumens formed therein and extending parallel to each other in an axial direction thereof. The two guide wires are inserted in the two lumens, respectively, such that a front end portion of each of the two guide wires projects frontward from a corresponding one of the two lumens and the each guide wire is movable in the axial direction. More specifically described, each guide wire may be inserted in the corresponding lumen in a so-called “monorail” manner in which the guide wire is inserted in the lumen through an opening formed in an outer circumferential surface of an axially intermediate portion of the main body, and is caused to project outward from an opening formed in a front end of the main body as seen in an insertion direction in which the main body is inserted in the human body, or in a so-called “over-the-wire” manner in which the guide wire is inserted in the lumen through an opening formed in a rear end surface of the main body as seen in the insertion direction, and is caused to project outward from an opening formed in the front end of the main body.
The above-indicated so-called “double-guide-wire” catheter through which two guide wires can be extended can find various applications. For example, in a state in which the main body of the catheter is inserted in a blood vessel having a total occlusion lesion, the two guide wires are moved forward in the two lumens, respectively, and respective front end portions of the two guide wires that project frontward from the main body are operated to pass through through the lesion and thereby treat the same.